Fixes small typo in WL attribute

[vicford]

Description of PR

The warming level attribute description had a small typo "Celcius". Fixed to "Celsius".

Summary of changes and related issue

Fixed a typo, and relevant other comments with typo.

Relevant motivation and context

Typo.

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Definition of Done Checklist

How to test: Retrieve data at a desired warming level and check the warming level attribute description. For example: ds.warming_level

Practical

• [N/A] 80% unit test coverage
• [N/A] Documentation
  • [N/A] All functions/adjusted functions documented in the readthedocs.
  • [N/A] Documentation is pushed
• [N/A] Complex code commented
• [x] Naming conventions followed
  • [N/A] Helper functions hidden with _ before the name
• [N/A] Context of function is clearly provided
  • [N/A] Intent of function is provided
  • [x] How to test, so that it is not siloed on scientists and anyone can review
  • [x] Appropriate manual testing was completed
• [x] Any notebooks known to utilize the affected functions are still working
• [x] Linting completed and resolved

Conceptual

• [x] Doesn't replicate existing functionality
• [x] Aligns with general coding standard of existing functions
• [x] Matches desired functionality from users/scientists